Question: Simplify the following expression: $\sqrt{117} - \sqrt{13}$
Answer: First, try to factor any perfect squares out of the radicals. $= \sqrt{117} - \sqrt{13}$ $= \sqrt{9 \cdot 13} - \sqrt{13}$ Separate the radicals and simplify. $= \sqrt{9} \cdot \sqrt{13} - \sqrt{13}$ $= 3\sqrt{13} - \sqrt{13}$ Finally, simplify by combining the terms. $= ( 3 - 1 )\sqrt{13} = 2\sqrt{13}$